Understanding Arc Fault Detection Devices (AFDDs): Are They Worth Installing?

The introduction of the 18th Edition of the IET Wiring Regulations (BS 7671:2018) brought significant changes to the electrical industry — one of the most debated being the recommendation to install Arc Fault Detection Devices (AFDDs).

Initially met with confusion and often overlooked due to being only a recommendation, the situation has changed with Amendment 2 of BS 7671, which now mandates their use in certain installations. At Switch Electrical & Mechanical Services Ltd, we believe it’s important to help clients understand what AFDDs are, when they’re required, and whether they’re the right option for your property.

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What is an AFDD?

According to the IET, AFDDs are protective devices installed within consumer units to detect and interrupt arc faults — a common cause of electrical fires. Unlike RCDs or MCBs, AFDDs use microprocessor technology to monitor the electrical waveform and detect unusual patterns that suggest arcing, especially in faulty or loose connections.

By automatically cutting power to the affected circuit, AFDDs help prevent potential fire hazards. They are most commonly installed on socket outlet final circuits, particularly in locations where people are more vulnerable — such as bedrooms, care homes, and student accommodation.

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What Does BS 7671 Say About AFDDs?

While BS 7671 is not a statutory document, it is widely followed as the industry standard. Compliance with The Electricity at Work Regulations 1989, Building Regulations 2010, and Part P is still legally required.

AFDDs are now mandatory on single-phase AC socket circuits (≤32A) in the following buildings: • Higher-Risk Residential Buildings (HRRBs) • Houses in Multiple Occupation (HMOs) • Purpose-built student accommodation • Care homes

In all other premises — including typical domestic homes — AFDDs are recommended, but not mandatory.

Where required, they must be installed at the origin of the circuit and comply with BS EN 62606.

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Challenges with AFDD Adoption

Just like RCBOs during their early adoption, AFDDs face two key issues: 1. Cost – They remain significantly more expensive than other circuit protection devices. 2. Availability – Certain brands and configurations can be difficult to source, especially at short notice.

This has led many electricians and customers to delay or forgo their installation. However, as the market matures, we expect both cost and availability to improve.

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What Do the NICEIC Say?

The NICEIC, one of the UK’s leading electrical certification bodies, recognises some key points: • Series arc faults in ring final circuits are not always detected by AFDDs. However, they are effective against parallel arc faults. • AFDDs should be advised and offered to customers during consumer unit replacements, especially in higher-risk environments. • If AFDDs are recommended (but not required), no coding is necessary in the EICR — but the absence should still be noted. • In high-risk settings where AFDDs are required, their absence during a periodic inspection should be marked with a C3 code (improvement recommended).

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Should You Install AFDDs in Your Home or Business?

The need to install AFDDs arises in new installations or when alterations or additions are made to existing installations — especially in sleeping areas or high-risk residential environments.

Even where they are not mandatory, we believe they offer an extra layer of safety. They are particularly beneficial in: • Older properties with historic wiring • Properties undergoing renovation or extensions • Environments housing vulnerable occupants

At Switch Electrical & Mechanical Services, we advise clients on a case-by-case basis and are happy to explain the benefits and practicalities based on your exact needs.

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What If You Can’t Install AFDDs Right Now?

In some cases, immediate installation of AFDDs may not be possible due to cost or supply issues. If this happens, we ensure: • You’re informed of the recommendation • Your decision is recorded on the Electrical Installation Certificate as a justified departure (if needed) • A plan is made for future installation, once the devices are available or affordable

This approach ensures transparency and compliance without compromising safety.

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Final Thoughts

Arc Fault Detection Devices represent the next step in proactive electrical fire prevention. While not always required, they are a forward-thinking upgrade for properties where electrical safety is a top priority.

At Switch Electrical & Mechanical Services Ltd, we always ensure that our clients receive honest, professional advice tailored to the regulations and the realities of your installation. If you’d like to explore AFDDs further — or discuss whether they’re suitable for your home or business — contact us today.

✅ Ready to upgrade your electrical protection?

Get in touch with our team for advice or a no-obligation quote. 📞 0191 9052723 💬 WhatsApp: 07388 439427 📧 switchtoday@mail.com

Frequently Asked Questions (North East UK)

What are my legal electrical responsibilities as a Landlord in Newcastle? As a landlord in the North East, you are legally required to ensure that all electrical installations in your rental property are safe when tenants move in and are maintained in a safe condition throughout the duration of the tenancy. This includes obtaining a satisfactory Electrical Installation Condition Report (EICR) every 5 years or at the start of a new tenancy. Switch Electrical & Mechanical Services provides comprehensive EICR audits for landlords across Newcastle, Sunderland, and Gateshead.

How much does an EICR cost for a standard property in the North East? The cost of an EICR depends on the size of the property and the number of circuits. Switch Electrical & Mechanical Services provides highly competitive, transparent pricing for landlords in the North East. We also offer discounted rates for landlords with multiple properties or HMOs requiring block certification.

What happens if my rental property fails an EICR? If an EICR identifies 'C1' (Danger Present) or 'C2' (Potentially Dangerous) codes, the installation is deemed 'Unsatisfactory'. Landlords have exactly 28 days to complete the necessary remedial work. Our team at Switch Electrical & Mechanical Services can provide immediate, fixed-price quotes for all remedial work following an inspection to ensure you remain legally compliant.